Thermistors Flashcards
what is the symbol for a thermistor
a resistor with a line going through it and along like this
_/
what is a thermistor?
a resistance thermometer
a resistor who’s resistance is dependant on the temperature
what is a key feature of a thermistor
the resistance of a thermistor decreases if the TEMPERATURE INCREASES
a circuit like this is found in computers:
a thermistor is in series with a cooling fan
explain why there is a cooling fan
when computers get hot, a cooling fan switches on and cools the computer back down
under cool conditions, what is the resistance of a thermistor like?
what does this mean for the pd across the thermistor?
high
high
takes a lot of energy for the current to pass through the thermistor
the pd across the thermistor is HIGH
pd is shared between the components in series so the pd across the fan is small
the pd across the fan is small, what does this mean for the fan
the fan will operate at a very low speed
what happens to the resistance of the thermistor when the computer gets hot?
the resistance of the thermistor falls
meaning it’ll take much less energy for the current to pass through the thermistor
the pd across the thermistor is low because the resistance of the thermistor is now very low,
what will this mean for the fan in series with the thermistor?
more electrical energy is available for the fan
very high potential difference across the fan
the fan powers up to high speed to cool the computer back down
high pd of the fan makes the fan what?
the fan is in a circuit which is found in a computer , explain what the fan does at a high potential difference.
operate at a high speed cooling the computer back down
what system does an incubator for premature babies contain?
a system to deflect faults
what happens if the temperature falls in an incubator?
it is sensed by a thermistor
this causes a lamp to turn on and an alarm to sound
